The goal in this study is to fabricate an intravascular glucose sensor that functions accurately for 3 days in vivo. To do this, we will develop an outer membrane that facilitates the conversion of endogenous S- nitrosothiols to nitric oxide locally at the membrane/blood interface. Since nitric oxide is released by the endothelial cells and is responsible for maintaining vascular tone and platelet inactivation, this is a natural approach that mimics the functions of the endothelium. This study involves the design of a biocompatible glucose-selective membrane, fabrication of a functional glucose sensor, and bench and animal testing to assess biocompatibility and function of the sensor. Continuous monitoring of blood glucose levels has been an elusive goal, but would greatly improve the care for critically ill patients in managing insulin therapy. [unreadable] [unreadable]